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Abstract

Background

Urban water sources of Khamis Mushait Governorate, southwestern Saudi Arabia, were
studied to assess their bacteriological characteristics and suitability for potable
purposes. A cross-sectional epidemiological method was adopted to investigate the
four main urban water sources (i.e. bottled, desalinated, surface, and well water).
These were sampled and examined between February and June 2007.

Results

A total of 95 water samples from bottled, desalinated, surface, and well water were
collected randomly from the study area using different gathering and analysing techniques.
The bacteriological examination of water samples included the most probable number
of presumptive coliforms, faecal coliforms, and faecal streptococci (MPN/100 ml).
The results showed that the total coliform count (MPN/100 ml) was not detected in
any samples taken from bottled water, while it was detected in those taken from desalinated,
surface, and well water: percentages were 12.9, 80.0, and 100.0, respectively. Faecal
coliforms were detected in desalinated, surface, and well water, with percentages
of 3.23, 60.0 and 87.88, respectively. About 6.45% of desalinated water, 53.33% of
surface water, and 57.58% of well water was found positive for faecal streptococci.
Colonies of coliforms were identified in different micro-organisms with various percentages.

Conclusion

Water derived from traditional sources (wells) showed increases in most of the investigated
bacteriological parameters, followed by surface water as compared to bottled or desalinated
water. This may be attributed to the fact that well and surface water are at risk
of contamination as indicated by the higher levels of most bacteriological parameters.
Moreover, well water is exposed to point sources of pollution such as septic wells
and domestic and farming effluents, as well as to soil with a high humus content.
The lower bacteriological characteristics in samples from bottled water indicate that
it is satisfactory for human drinking purposes. Contamination of desalinated water
that is the main urban water source may occur during transportation from the desalination
plant or in the house reservoir of the consumer. Improving and expanding the existing
water treatment and sanitation systems is more likely to provide safe and sustainable
sources of water over the long term. Strict hygienic measures should be applied to
improve water quality and to avoid deleterious effects on public health, by using
periodical monitoring programmes to detect sewage pollution running over local hydrological
networks and valleys.

Background

High-quality water sources may be required only for drinking purposes, while the quality
of water for other domestic uses can be quite variable. Therefore, water polluted
to only a certain extent can be considered pure [1]. With an increasing urban population density of the study area, the scarcity and
pollution of surface water poses a serious problem for urban drinking water supplies
of metropolitan areas [2-7]. Consequently, water resources are a key factor, particularly for planning a sustainable
socioeconomic development [8,9]. Bottled water, however, is being widely consumed because it contains fewer impurities.
Therefore, it can also be beneficial to detect deterioration in the quality of water
resources and to facilitate appropriate and timely corrective actions with a minimal
negative impact on public health [10-14].

For the last three decades, many countries in arid and semi-arid regions have depended
heavily on the desalination of seawater to meet their growing needs. Saudi Arabia
is considered one of the biggest efficient producers of freshwater by desalination,
with an installed capacity of more than 1000 million USGPD, accounting for 24.4%>
of the world's desalinated water production [15,16]. In the case of Saudi Arabia, surface water sources (i.e. dams, lakes, and open water
reservoirs) are considered to be very limited resources and are exploited for almost
every use. They are also exposed to urban wastewater disposal from both wastewater
stations (that has not reached secured stages 3–4 in most of the Saudi wastewater
stations 70%, causing an expected environmental pollution especially around metropolitan
areas), which has made the surface water resources highly polluted, especially in
parched valleys. The frequent outbreaks of waterborne diseases are the result of a
direct discharge of untreated or partially treated domestic sewage water sources located
beside local gutters [1,17,4].

Groundwater is still and will continue to be the main source of safe and reliable
drinking water, especially in rural areas in Saudi Arabia. Water taken from such sources
(different types of shallow and deep wells) is often of better quality than surface
water or other open water sources if the soil is fine-grained and its bedrocks do
not have cracks, crevices, and bedding plants, which permit the free passage of polluted
water especially within metropolitan zones [7,30,37,7,20]. It is often assumed that natural, uncontaminated water from deep wells is clean
and healthy, and this is usually true with regard to bacteriological composition [21]. However, bacterial pollution of water sources may occur and is mostly derived from
watershed corrosion as well as drainage from sewage, swamps, or soil with a high humus
content. This type of hazard exists particularly in limestone areas where underground
chambers or fissures may permit water to flow in the freely moving streams without
substantial filtrations. Such suspected water sources cannot be used without caution
for human drinking purposes because of the inherent health risks [22,16,17,24,4-7,11].

The major interest of public health authorities in developing quality standards for
urban water uses is focused on the recognition, enumeration, identification, and assessment
of microorganisms related to waterborne diseases that are considered indicators of
microbiological parameters [25,17,5,7,11,26]. These indicators are of great importance to assess the microbial condition of the
examined water sources [27]. Moreover, the bio-indicator of faecal pollution is a non-pathogenic microorganism,
whose detection suggests the presence of enteric pathogens. Usually, coliforms, faecal
coliforms, and faecal streptococci are recognised as the main indicators of microorganisms
in water sources [26,9]. These indicators are of significance to assess the microbial condition of the water
supply [28]. Microorganisms as an indicator of faecal pollution should satisfy several criteria
[29,20]. For instance, they should be present in faeces in greater numbers and have more
resistance than any pathogen to the stresses of an aquatic environment [30,31,17,4,26]. The evaluation of total coliforms may sometimes give erroneous information regarding
faecal contamination [32,17,4,11,26,12].

The main objective of this study was to assess the bacteriological water quality and
its geospatial relations of the four major urban water sources in the study area (bottled,
desalinated, surface, and well water) which have been the focus of the community [23,5-7]. An attempt was also made to identify the coliforms isolated from the examined water
samples (Table 1). The findings may be considered as a basis for water health policy decisions at
different administrative levels in the study area.

Results and discussion

Data recorded in Figure 1 indicated that total coliforms were not detected in any sample taken from bottled
water. In the desalinated water, surface water, and well water, total coliforms were
detected with percentages of 12.9, 80, and 100.0, respectively. However, log counts
of total coliform bacteria (MPN/100 ml) in desalinated, surface, and well water were
0.0–1.60, 0.0-≥ 4.38, and 1.60-≥4.38, respectively. The log mean values were 3.79
± 3.40 and 3.86 ± 3.22 (MPN/100 ml) in samples taken from surface and well water,
respectively. In previous studies, total coliform bacteria were detected in different
water sources with various mean values and percentages [28,31,23,33,34]. There was no significant correlation in the level of total coliforms between well
and surface water. As previously cited, total coliform counts must not be detected
in any 100 ml water samples [35,17,24,11]. Therefore, results of total coliforms recorded in the present study showed that
all examined samples from wells (100.00%) and most surface water (80.00%) exceeded
the guideline values recommended in accordance with international standards [3,17,24].

The most common group of indicator organisms used in water quality monitoring are
coliforms. These organisms are representative of bacteria normally present in the
intestinal tract of mammals including human, so they provide a general, albeit adequate,
index of faecal contamination of drinking water [36,24,26,38]. Moreover, the presence of coliforms in drinking water could also indicate a breakdown
of the treatment process [28]. The transportation of desalinated water by tanker does not contribute significantly.
Such contamination obviously occurs during storage in the house reservoir (earth)
and is possibly implicated, at least partly, in the increased prevalence of diarrhoea
[23].

From the results recorded in Figure 2, it is evident that faecal coliforms were not detected in any samples taken from
bottled water, while from desalinated water, only one out of 31 (3.23%) samples was
found positive for faecal coliforms. However, 9 out of 15 (60.0%) and 29 out of 33
(87.88%) specimens were found positive for faecal coliforms in samples taken from
surface and well water, respectively. The log counts of faecal coliforms (MPN/100
ml) ranged from 0.0 to 1.6; 0.0 to ≥ 4.38 and 0.0 to ≥ 4.38 in desalinated, surface,
and well water, respectively. Logarithmic mean values (MPN/100 ml) were 3.47 ± 3.23
and 3.40 ± 3.08 in surface and well water, respectively. There was no significant
correlation in the level of faecal coliforms between well and surface water. These
results indicated that most samples taken from wells (87.88%) and surface water (60.00%)
had higher faecal coliforms with respect to the international guideline value, in
which drinking water must be free from faecal coliforms [22,17,24,11,26,9]. Different coliform counts were previously recorded in groundwater samples [28,31,23,39,40].

Indicators such as faecal coliforms are not the best, because their effectiveness
will be minimised in geographical zones when the temperature is high [41,26,42]. However, well water is at risk of contamination, as indicated by the presence of
faecal coliforms [43,24,5,7,11,44,20].

It is evident from Figure 3 that faecal streptococci were not detected in any samples taken from bottled water.
Two out of 31 (6.45%) desalinated water samples, 8 out of 15 (53.33%) surface water
samples, and 19 out of 33 (57.58%) well water samples were found positive for faecal
streptococci. Logarithmic range values of faecal streptococci (MPN/100 ml), however,
were 0.0–1.6, 0.0–2.18, and 0.00–3.38 in samples taken from desalinated, surface,
and well water, respectively. The log mean values of faecal streptococci (MPN/100
ml) were 1.65 ± 1.07 and 2.28 ± 1.97 in surface and desalinated water. There was a
significant correlation at p = 0.05 in the level of faecal streptococci between surface
and well water. With regard to international guideline values, in which water must
be free from faecal streptococci, 6.45% of the desalinated water, 53.33% of the surface
water, and 57.58% of the well water was considered to be unfit for drinking purposes.
Faecal streptococci were previously isolated with various frequencies [28,31,33]. Enterococcus species were formerly classified in the genus streptococci. They are
primarily commensurate with residence in the intestine, though some also cause gastroenteritis,
nosocomial infection, endocarditis, intra-abdominal infection, surgical wound infection,
and urinary tract infections [45,46,19,17,24,11].

As regards the bacteriological examination of water sources carried out in this study,
high total coliforms, faecal coliforms, and faecal streptococci in surface and most
well water are considered an indication of recent faecal pollution from human or animal
excreta, which may reflect the possibility of potential health hazards [42]. The primary risk of consuming untreated water is the transmission of communicable
diseases by pathogenic organisms. Those present in aquatic environments can be of
natural origin or may be discharged by humans and other warm-blooded animals. However,
the water, which is not suitable for drinking, may be usable for irrigation or for
other domestic purposes. Thus, it can be seen that each use of water imposes its own
limits on the degree of pollution that can be considered acceptable [1,17,24]. Drinking only from desalinated water sources was associated with diarrhoea as compared
with drinking only from bottled water or from any other sources [23]. Water from the valleys and wells of the study area was grossly polluted and was
used regularly for purposes other than drinking [23,5-7].

The coliform group comprises strains of the four genera of the intestinal group: Escherichia,
Enterobacter, Klebsiella, and Citrobacter. The number of Escherichia and Enterobacter
remains much higher in the intestine than do the remaining two [1,26,9].

The frequency distribution of the different microorganisms isolated from the examined
samples is given in Table 1. A total of 114 isolated bacteria included 10 from desalinated water, 45 from surface
water, and 59 from wells. These were typed to be 23 Escherichia coli (E. coli), 13
Klebsiella pneumonia, 7 Klebsiella oxytoca, 20 Enterobacter cloacae, 6 Eenterobacter
aerogens, 7 Eenterobacter agglomerans, 3 Enterobacter gergoviae, 10 Citrobacter freundii,
8 Citrobacter diversus, 12 Proteus vulgaris, and 5 Proteus mirabilis, with percentages
of 20.18, 11.40, 6.14, 17.54, 5.26, 6.14, 2.63, 8.77, 7.02, 10.52, and 4.39, respectively.
Most of these bacterial species had been previously isolated from different water
sources, although their percentages varied [47,27,31,40,11].

It is clear that out of all possibilities, E. coli can best fulfil conditions possible
to act as an ideal indicator of faecal pollution. These organisms survive longer in
water than most pathogens, and thus can detect recent as well as earlier pollution.
In terms of public health significance, E. coli has frequently been reported to be
the causative agent of traveller's diarrhoea, urinary tract infection, haemorrhagic
colitis, and haemolytic uraemia syndrome. Moreover, Klebsiella pneumonia is associated
with pneumonia and upper respiratory tract infection. However, Enterobacter and Citrobacter
species have also been previously reported as causes of cystitis, enteritis, pneumonia,
diarrhoea, and food poisoning [48,17,24,11]. Proteus species are apparently of epidemiological importance in summer diarrhoea
in infants and in food-borne outbreaks. Proteus vulgaris in association with other
bacteria has been reported to be the causative agent of cystitis and pyelitis [48,25,17,24,11].

Based on the above assessments, although bottled water may be of good quality in the
Khamis Mushait Governorate urban area, the public supply of both desalinated water
distributed via an urban water network system to areas of city quarters and conventional
water sources such as wells and surface water cannot be ignored by local water authorities.
They should consider a proper regular monitoring programme (i.e. wells and surface
water microbial source tracking system) to determine the primary sources of contamination,
their contribution, health threat, and geographic distribution. In addition, they
ought to make recommendations and to develop appropriate control measures to avoid
any sudden public health risk from such a vital water source [23,11].

Conclusion

Water derived from traditional sources (wells) showed increases in most of the investigated
bacteriological parameters, followed by surface water as compared to bottled or desalinated
water. This may be highly attributed to the fact that well and surface water of Khamis
Mushait Governorate is at risk of contamination as indicated by the higher levels
of most bacteriological parameters. Moreover, well water is exposed to point sources
of pollution such as septic wells and domestic and farming effluents as well as to
soil with a high humus content [4,11]. The lower bacteriological characteristics in samples of bottled water indicate that
it is satisfactory for human drinking purposes. Nevertheless, contamination of desalinated
water may occur during its transportation from the desalination plant to the consumer
or during storage in a house reservoir. Improving and expanding the existing water
treatment and sanitation systems is more likely to provide good, safe, and sustainable
sources of water in the long term. Strict hygienic measures should be applied to improve
water quality and to avoid deleterious effects on public health [3,6,11]. This could be achieved by upgrading current sewage stations (i.e. to deal with stages
3 and 4) and adopting a periodical monitoring programmes to detect sewage pollution
in water supplies, [23,5-7,14] thus eliminating the possibility that disease may be transmitted by their use or
during their running through the local hydrological network and valleys as have been
noticed via satellite digital mapping of the study area [17,4,6].

Methods

Study area, design, samples, and materials

The study area

The study was conducted in an urban zone of Khamis Mushait Governorate (about 43 km
× 25 km centred at 18.3° N, 42.8° E [42], with a population of 497,000 [2007]), which covers about 1075 km2, with an elevation ranging from about 982 to 1946 m (mean 1464 m) above sea level,
an average annual rainfall of 355 mm (range 160–450 mm), it has a two short rainy
seasons, 70% of which occurs in March and May (ranges between 40–55 mm) and August
and September (ranges between 36–62 mm) with about 300 mm/y and average minimum and
maximum temperatures of 19.3 C and 29.70 C, respectively [17,5-7].

Design

In this study, a cross-sectional epidemiological method was used to assess representative
samples of the four main urban water sources (i.e. bottled, desalinated, surface,
and well water; see Table 1) in Khamis Mushait Governorate, southwestern Saudi Arabia. These representative samples
were examined between February and June 2007 to assess their bacteriological characteristics
and suitability for potable purposes. Using a simple random sampling technique, a
total of 95 drinking water samples were collected from bottled water, desalinated
water, surface water, and groundwater (wells of different types).

Sampling and materials

Simple random sampling was the method chosen for this study. Geographical settings
of both the surface water and wells were determined in advance via a digital satellite
mapping processing technique (Erdas Map sheet, v.9 and Global Mapper Software, LLC
v. 10) by using the Google Earth digital mapping engine (a paid copy of Google Earth
pro™) to obtain an overview, to ease virtual navigation, and to refine the micro-geographic
data when mapping the Khamis Mushait administrative area [49,5-7]. (Satellite images are aerial photographs and do not represent real time; they have
an average high resolution age of several years and a spatial resolution of 25 m per
pixel or even higher [15 m] in some areas) [42].

The network sampling method offered options that may have been more efficient for
this study than classical sampling [50]. It employed good local knowledge, including of streets, in determining targeted
water groups, their geographic distribution, and boundaries using Google Earth digital
maps as a powerful platform in improving micro-sampling, processing, field manipulations
and operations, tracking, allocation, and high-quality map creation. All of these
elements supported the training of the research sampling team and helped in understanding
the spatiotemporal relationship and geographic patterns between all entities. Composite
maps of different types (i.e. hand drawn maps) were also used efficiently by the researcher
and the field support team for the disk and ground phases.

For bottled water, sixteen brands (known to the local community) consisting of spring
and purified bottled water types were purchased from different local supermarkets
within Khamis Mushait Governorate and sampled. For desalinated water, 31 water samples
were obtained from Ashiab (i.e. distributing points for the Khamis Mushait Governorate water desalination station),
using the simple random sampling technique, from water trailers, houses, urban water
networks, fish markets, and slaughterhouses. For surface water, 15 specimens were
collected from the selected sites, the Tandaha dam reservoir and valleys around Khamis Mushait Governorate, using the simple random
sampling technique. From wells, 33 water samples were also selected from the chosen
geo-sites of different types of wells located around the study area, using the simple
sampling technique. Planning of both the surface and groundwater samples was carried
out, and the specimens were assessed using spatial techniques (i.e. network method)
for the digital satellite map of Khamis Mushait Governorate, using the Google Earth
mapping engine [42].

Samples from each brand of bottled water were kept in a screw capped 1.5-litre plastic
container. Samples from desalinated, surface, and well water were collected under
completely sterile conditions and placed in sterile, screw capped, 150-ml plastic
bottles, taking into consideration the standard methods of both gathering and handling
water samples. All specimens of desalinated, surface, and well water were sampled
and dispatched daily, with a minimum delay, in an FWD Car (provided by King Khalid
University to the author and his trained sampling team [E AlOtaibi, MSA Zaki A Ghorm,
and N Alshahrani]) to the Medical Laboratory Technology Department, Khamis Mushait
Community College. Most water quality constituents were determined within 2–6 hours
of collection [3].

The bacteriological examination of water samples includes Most Probable Number (MPN)
of presumptive coliforms, faecal coliforms, and faecal streptococci (MPN/100 ml water)
using the Multiple Tube Fermentation Technique [3,26]. Suspected colonies of coliform groups were also identified on the basis of morphological,
cultural, and biochemical characteristics [51,9]. Significant differences between each two means were evaluated using SPSS-PC Version
11 of the Student-T-Test [52].

Quality assurance procedures

Sampling strategy and design

Disk preparation phase

○ Adoption of a two-stage sampling scheme.

○ Careful planning and choice of representative sampling groups and sites according
to the adopted network sampling technique, and determining certain criteria such as
control sites where major sampling groups exist (i.e. surface water points, valleys,
and wells), impact sites where contamination is expected, such as polygons, and outlets
(e.g. treated water discharges site) to maximise understanding the quality of urban
water sources, and with the least risk of missing the correct representative sampling
groups and sites.

○ Attention paid to ensure inclusion in the sampling frame of all groups and locations
(sites, roads, venues, and so on) via screening, browsing, and delineation from a
satellite digital map of the Khamis Mushait Governorate zone, because local pre-knowledge
was preferred with regard to accessibility, safety, and permission.

○ Approximation of the number of the target study population in each group and sampling
location.

○ Determination of the proportional allocation of samples between different groups
and locations.

○ Training of interviewers\sample collectors to follow and to use the sampling strategy
and procedures.

○ Implementation of ways to boost participation rates in the screening and core interviews
and sample collection.

During analysis phase

○ Perform standard analysis procedures.

○ Compare results and findings of each sample within each group with their auxiliary
data and other associated characteristics written on sample card to verify and to
make sure it belongs to the same group and sampled location; assess reasons for refusal
if there are any and determine whether refusal is associated with selection biases
or just handling, and report immediately.

○ Assess representativeness of the selected samples by comparing the data with other
data.

○ Incorporate weights into the analyses to reflect unequal probabilities of selection,
incomplete sampling frame, and rates of refusal samples.

○ Assess the need to use statistical programmes that incorporate the design effect
of such a cross-sectional study.

○ Compare findings relating to the collected samples with expected results of the
groups.

Acknowledgements

The author would like to express his thanks to the Administration of King Khalid University
for meeting logistic needs, as well as to his colleagues, staff, and his postgraduate
students of the Geography Department, School of Human Sciences (i.e., PG: M S Dh.
AlSalim was supervised partially by the author) and the Department of Applied Medical
Sciences Laboratories, Khamis Mushait Community College, King Khalid University, for
their help and support and useful advice during the course of this study. Special
thanks are due to MSA Zaki, Professor of Epidemiology and Environmental Health and
Chairman of the Department of Applied Medical Sciences Laboratory, and his colleagues,
for their help in analysing and interpreting the study samples. Finally, conclusions
contained herein are those of the author, based upon the study's findings, and should
not be interpreted as necessarily representing either regional and/or national official
policies or endorsement, or as expressing or implying the interests of any organisation
or any person connected with them. Last but not least, my appreciation also goes to
the anonymous reviewers for their useful comments.

References

Goel PK: Water pollution: causes, effects and control. New Delhi-110002, India. H.S. Poplai, New Age International (P) Limited; 1997.

Ortiz RM: Assessment of microbial and chemical water quality of individual and small system
groundwater supplies in Arizona. PhD thesis. University of Arizona, Department of Soil and Environmental Science; 2007.

Zaki MSA, Byomi AM, Hussein MM: Hygienic evaluation of water used in some broiler farms around Sadat city in Menoufia
governorate.

Procs of the 6th Vet Med Zagazig Conference 2002, 209-224.

Dutka BJ: Microbiological indicators, problems and potential of new microbial indicators of
water quality. In Biological Indicators of Water Quality. Edited by James A, Evison. New York: John Wiley&Sons; 1979:1-27.

Food and Agriculture Organization: Remote sensing and its application to investment project identification and preparation:
a study with special reference to the FAO investment center. Edited by Lantieri D, Gastellu-Etchegorry JP. Food and Agriculture Organization of the United Nations; 1993.